memory: pass EventNotifier, not eventfd

Under Win32, EventNotifiers will not have event_notifier_get_fd, so we
cannot call it in common code such as hw/virtio-pci.c.  Pass a pointer to
the notifier, and only retrieve the file descriptor in kvm-specific code.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/exec.c b/exec.c
index 8244d54..29b5078 100644
--- a/exec.c
+++ b/exec.c
@@ -3212,13 +3212,13 @@
 
 static void core_eventfd_add(MemoryListener *listener,
                              MemoryRegionSection *section,
-                             bool match_data, uint64_t data, int fd)
+                             bool match_data, uint64_t data, EventNotifier *e)
 {
 }
 
 static void core_eventfd_del(MemoryListener *listener,
                              MemoryRegionSection *section,
-                             bool match_data, uint64_t data, int fd)
+                             bool match_data, uint64_t data, EventNotifier *e)
 {
 }
 
@@ -3278,13 +3278,13 @@
 
 static void io_eventfd_add(MemoryListener *listener,
                            MemoryRegionSection *section,
-                           bool match_data, uint64_t data, int fd)
+                           bool match_data, uint64_t data, EventNotifier *e)
 {
 }
 
 static void io_eventfd_del(MemoryListener *listener,
                            MemoryRegionSection *section,
-                           bool match_data, uint64_t data, int fd)
+                           bool match_data, uint64_t data, EventNotifier *e)
 {
 }